CopperSharp68k

CopperSharp68k is a closed-world CIL-to-Motorola 68000-family ahead-of-time compiler for C# and other .NET languages.

The current target emits 68k code with Amiga HUNK executable, Kickstart ROM, and assembler output support. Amiga platform bindings and library-call resolution live in the SDK and Amiga integration projects; the compiler core is kept separate so additional targets such as MorphOS/PPC can be added later.

Projects

• Compiler - compiler core, 68k backend, HUNK/ROM/assembly output.
• Compiler.Cli - command-line driver.
• Targets.Amiga - Amiga library-call resolver and platform helpers.
• Sdk.Amiga - Amiga ABI declarations for compiled code.
• Compiler.Tests - compiler tests. These use a sibling MedPlayer/Copper68k checkout when available, otherwise the Copper68k package.

Build

dotnet build CopperSharp68k.slnx
dotnet test CopperSharp68k.slnx

.NET 10 compatibility profile

CopperSharp compiles an explicitly bounded subset of ordinary net10.0 assemblies using exact framework bindings, verified implementation packs, a private managed runtime, and an Amiga platform layer. It never discovers an installed host runtime implicitly. Start with the consolidated .NET 10 profile documentation; the exact member inventory remains machine-readable in the profile manifest.

Pinned CoreLib is the recommended Stopwatch implementation when a verified pack is available, with ShadowStopwatch retained as a deterministic fallback. The retained cross-CPU comparison is in compatibility and performance testing.

Admitted System.Math surface

The net10.0/10.0.9 compatibility ledger admits the exact integral overloads of Abs, Min, Max, Clamp, and Sign that fit the current scalar ABI, plus the 32-by-32-bit signed and unsigned BigMul forms. It also admits the float/double overloads of Abs, Min, Max, Clamp, and Sign, Math.CopySign(double, double), the core Single/Double IEEE classifiers, and Floor, Ceiling, Truncate, Round, and Sqrt for double.

The portable implementations operate on IEEE bit patterns and run in SoftFloat mode without a floating-point arithmetic runtime. Native FPU modes lower Sqrt and Truncate leaves to FSQRT and FINTRZ; the other rounding modes use the deterministic software path so their result does not depend on ambient FPCR rounding state. Decimal, Int128/UInt128, tuple-returning DivRem, digit-count Round overloads, MathF, and transcendental functions remain fail-closed.

CopperScreen emulator tests

Compiler.Tests contains end-to-end tests that compile CompilerFixtures to Amiga HUNK executables and run them with CopperScreen's deterministic headless runner. The matrix checks arithmetic/control flow and exception handling on accurate-interpreter and JIT paths for MC68000 output, plus MC68040 output on the MC68040 JIT. Focused cases cover managed runtime faults and cross-method unwinding, 64-bit/multiword ABI behavior, virtual/interface dispatch, capturing delegates across forced collection, static type initialization, managed arrays and strings, and native MC68040 floating-point execution. The managed-pool cases force collection and verify that live caller-frame and closure roots survive.

When the sibling MedPlayer/CopperScreen.Headless.Cli project exists, it is built with the tests and its Debug or Release output is discovered automatically. Otherwise, point to the executable or managed DLL explicitly:

$env:COPPERSCREEN_HEADLESS_CLI = 'D:\Koodit\GIT\MedPlayer\CopperScreen.Headless.Cli\bin\Debug\net10.0\CopperScreen.Headless.Cli.exe'
dotnet test .\Compiler.Tests\CopperSharp.Compiler.Tests.csproj --filter 'Category=Emulator'

The emulator process is bounded by both instruction/frame limits and a host timeout. Missing CopperScreen binaries skip this optional category; an invalid explicit path fails with a configuration error.

WinUAE smoke tests

The slower machine-boot smoke layer builds a bootable 880 KiB ADF containing a small custom bootblock and a managed CopperSharp68k fixture. It boots the same ADF with Kickstart 1.3 and 3.1 in WinUAE; no Workbench disk, filesystem commands, or dos.library startup is required. The managed fixture obtains its arena through Kickstart Exec AllocMem, drops an allocation, forces a mark/sweep collection, verifies a live root and replacement allocation, and releases the arena through FreeMem; explicit AvailMem calls additionally check the public Exec register ABI. It returns a fixed value, and the host reads it from guest memory through WinUAE's headless IPC endpoint with a strict timeout. A marker in the final ADF sector remains as a fallback for emulators that flush guest writes directly to the image.

Run both locally available ROM profiles:

.\scripts\run-winuae-smoke.ps1

The defaults discover WinUAE under C:\Program Files\WinUAE and the sibling CopperScreen Kickstart 1.3/3.1 ROMs. Portable CI agents should provide paths explicitly or set COPPERSHARP_KICKSTART13_ROM and COPPERSHARP_KICKSTART31_ROM:

.\scripts\run-winuae-smoke.ps1 `
  -WinUaePath 'C:\Tools\WinUAE\winuae64.exe' `
  -Kickstart13Path 'D:\ROMs\kick13.rom' `
  -Kickstart31Path 'D:\ROMs\kick31.rom'

Use -Kickstart 1.3 or -Kickstart 3.1 for one profile, -DryRun to build and inspect generated configuration without launching WinUAE, and -KeepArtifacts to retain the ADF and .uae file. Kickstart 3.1 also runs freestanding MC68040 integer and native-FPU probes; use -M68040Only to run only those two profiles. Each profile receives its own generated ADF. Every image is also a normal bootable ADF that can be mounted in CopperScreen; CopperScreen's current automated integration uses the faster direct-HUNK headless path described above.

To produce a reusable image without launching an emulator:

.\scripts\build-amiga-smoke-adf.ps1 `
  -OutputPath .\artifacts\CopperSharp68k-Smoke.adf

The AmigaDOS example test uses a separate, genuine bootable OFS image. It contains the compiled DOS, FileStats, portable ConsoleIO, Polymorphism, and StopwatchBenchmark examples, successful test inputs, S:startup-sequence, and a minimal C:Execute implementation compiled from C#. The startup sequence redirects input and output for ConsoleIO, then a compiled verifier checks every captured byte. The WinUAE harness boots to the Kickstart CLI, enters the startup command, and waits for a result file written only after all checks pass:

.\scripts\run-winuae-dos-examples.ps1

Use -Kickstart 1.3 or -Kickstart 3.1 to select one ROM. Build the reusable filesystem image without launching WinUAE with:

.\scripts\build-amiga-dos-examples-adf.ps1 `
  -OutputPath .\artifacts\CopperSharp68k-DOS.adf

The low-level PAL OCS CopperBars demo has its own AmigaDOS ADF test. The WinUAE harness runs Kickstart 3.1 on an A500-compatible, cycle-exact MC68000 profile, clicks the left mouse button to exercise the demo's clean-exit path, and waits for the startup sequence to write a success marker after control returns:

.\scripts\run-winuae-copper-bars.ps1

Build the standalone demo image without launching WinUAE with:

.\scripts\build-amiga-copper-bars-adf.ps1 `
  -OutputPath .\artifacts\CopperSharpCopperBars.adf

This layer is intended for nightly or pre-release validation rather than the normal unit test gate.